Ashmolean Museum Observatory [AMO] (c.1730-1735 [?]), the Old Ashmolean Building where James Bradley is known to have used a portable transit instrument from the lower half landing on the principal staircase, with a view south over the city (Howse 1986; Gunther 1923, 86).
City Wall Observatory [CWO] (1740-1760), off New College Lane, for the use of the Savilian professor. Nathaniel Bliss sometimes used fixed instruments mounted on the massive section of the old city wall immediately adjacent to the two houses of the Savilian professors of Astronomy and of Geometry (Howse 1986; Gunther 1923, 86-7).
Corpus Christi College Observatory [CCCO] (1763-1773), private, used by Hornsby with his new portable mural quadrant (32-inch) by John Bird with a 1¼-inch OG by Dollond, from the window of his room. He took this instrument with him to the new Radcliffe Observatory which he founded in 1772, and installed it in the Students’ Observatory there. The instrument is now in the MHS (Howse 1986; Gunther 1923, 87).
Keble College Observatory [KCO] (c.1889-92), in January 1889 the College received ‘An Equitorial (sic) from a Mr Lowe’, and shortly afterwards the College voted £25 to house it. Elsewhere a Dallmeyer telescope was mentioned, without noting its size. Unfortunately the records for the next decade are missing, and nothing is known of whether the telescope was used, where it was located, or its fate. The donor may have been Hubert Foster Lowe (1861-1938), mathematician and chemist, who obtained a First in 1882 and stayed on in Oxford until 1884 as a physics demonstrator.
Magdalen College Observatory [MCO] (1857-1902), established after Charles Daubeny, Professor of Botany, influenced by John Phillips, gave to the College a 5½-inch Cooke refractor in 1855. It was mounted upon the roof of an especially designed and strengthened ‘Telescope Room’, and provided with a run-off shed. This was the first purpose-built college observatory in Oxford. Professor H. Hilton used the telescope to observe double stars using Celestial Objects for the Common Telescope (2nd Eds., 1868) by the Rev. Webb (Gunther 1923, 94-5).
‘Mathematical Tower’ Observatory [MTOO] (1619-1772) located at the Schools Quad, later known as the Bodleian Tower of the Bodleian Library quadrangle, in the centre of Oxford (c.51º45′N 1º15W) – a university observatory. The University made available the top room of the tower for the use of the Savilian professor of astronomy, together with the flat roof above on which he could mount his portable instruments. It was used by the Savilian professors Greaves, Ward, D. Gregory, Bradley and Hornsby. Instruments used include a mural quadrant (78-inch) by Elias Allen, a mural sextant (73-inch) and a transit instrument (43-inch focal length) by John Bird (Howse 1986; Gunther 1923, 78-80).
Merton College Observatory [MCOO] (14th century), first significant astronomy at Oxford achieved international renown before the Reformation. A couple of Fellows of Merton College, mathematicians of exceptional ability as well as medical physicians, created the first school of astronomy in England. John Ashindon or Ashinden, also called Eastwood (in one reference of 1338) was according to Anthony Wood the greatest mathematician and astronomer ever produced by Merton College. He inspired a succession of students applying themselves to mathematics and astronomy over the next 150 years. . Ashindon and Rede are believed to have used astrolabes to make observations from the south part of the city wall that is also the boundary of Merton College garden. They made improved calculations including the mean longitude of each planet for every 20 years, and published tables adapted for the latitude of Oxford that were a distinct improvement on the Spanish calculations – Alphonsine Tables (1272), Toledo (Gunther 1923, 55-6 & 76).
Radcliffe Observatory [ROO] (1772-1935), located on the Woodstock Road, Oxford (51º46′N 1º15′W). Founded by private trust it was housed in a neo-classical building (Henry Keene & James Wyatt) and used by the Savilian professor until 1839. Its original instruments include a pair of mural quadrants (8-foot), transit instrument (43-inch FL), zenith sector (11-foot 8-inch), equatorial sector (5-foot), all by Bird and portable 3½ and 4½-inch refractors by Dollond. Later significant instruments include a Herschel Newtonian reflector (7-foot Fl, 8-inch mirror) in 1812, a mural circle (6-foot) by Jones, heliometer (7½-inch OG) by Repsold, the ‘Carrington’ transit circle (5-inch OG) in 1854, the Barclay refractor (10-inch OG) by Cooke in 1887 and the Radcliffe photo/visual refractor (24/18-inch) by Grubb in 1903. In 1930 the Radcliffe Trustees accepted the offer of Lord Nuffield for the Observatory site, urgently needed for expansion of the city’s hospital, and decided to relocate the Radcliffe Observatory to South Africa (Burley & Plenderleith 2005, 63-101; Howse 1986; Gunther 1923, 88-91; Stroobant 1931).
Savilian Professor’s House Observatory [SPHO] (c.1705 & 1842-60), at New College Lane, provided by New College for the use of the professor. A small observatory built c.1705 by Edmund Halley on the roof of the house. It is believed that no fixed instruments were installed. It was only large enough to hold about three people, had only one small window on each side, and would have been used for teaching practical astronomy with hand-held instruments. The Observatory was used by Professor William Donkin 1842–60 only as a teaching observatory (Howse 1986; Gunther 1923, 83).
University Museum Observatory [UMO] (1860-1875), teaching observatory with 4-inch transit instrument and small brass altazimuth instrument – demolished 1885. The first observatory purpose built by Oxford University – fate of the instruments is not known (Hutchins 2008, 42-3).
University of Oxford Observatory [UOO] (1875-current), purpose-built observatory in the University Park, Oxford. First equipped with a 12-inch refractor by Grubb, the donated De La Rue reflector (13-inch speculum mirror), along with the ‘Barclay’ 4-inch meridian circle (1887), and a 13-inch Grubb astrograph (1897). Later a Vertical 35m solar telescope by Grubb Parsons was added with original building much modified – original instruments replaced with modern ones (Gunther 1923, 94-5; Stroobant 1931).
Private and Group Observatories
Blenheim Palace Observatory [BPO] (c.1772-1800), established by George Spencer (1739–1817), the fourth Duke of Marlborough at Blenheim Palace (51º50′N 1º21′W). He had many interests but his chief scientific interest was astronomy for which he had a passion. From Thomas Hornsby, at the Radcliffe Observatory, he learned the techniques for using astronomical instruments. The Duke built an observatory on the south-east tower of his palace in about 1780 that was equipped with a Ramsden Transit instrument, an 18-inch Gregorian reflector by James Short, a 6-foot radius quadrant and a small refractor by Tulley. Later in 1789 he began erecting another observatory on the south-west tower, but there is no mention of either after 1840 (Howse 1986, 66; Crossley and Elrington, 448-60).
Hanwell Community Observatory [HCOB] (1992- ), Hanwell, nr. Banbury, established a local group of amateur astronomers to promote astronomy through star parties and other events. The dark sky site provides access to three open-air, permanently mounted telescopes, with moveable shelters. These are the McIver-Patton 12.5-inch reflector, the 30-inch Hanwell reflector and the 30-inch John Wall dialyte refractor.
Shirburn Castle Observatory [SCOO] (1739-c.1800), established by George Parker, second earl of Macclesfield at Shirburn Castle (51º39′N 0º58′W). A brick-built structure, its location is not now known, but it had three rooms including a bedroom for the earl when he wished to rest after observing late. It was equipped with what was probably then the finest suite of instruments anywhere. These included mural quadrant, transit instrument, Tompion and Graham clock as well as an object glass of about 120 feet focal length. Parker employed two assistants to supplement his own observations, Thomas Phelps a stable boy and John Bartlett a shepherd (Howse 1986, 80).
Slatter’s Observatory [SOI] (1850-61), Rose Hill, Iffley, established by the Revd. John Slatter, while he was ‘Priest-in-Charge’ at Sandford-on-Thames. The brick and wood structure houses a 2-inch transit instrument (fl 42-inch) and a 4.5-inch equatorial refractor (fl 7-feet 4-inches), both by William Simms. The observatory was given when Slatter was appointed vicar of Streatley Berks (Weale 1851, 72; Obit., MNRAS, 60 (1900), p.325).